More than three billion prescriptions are written each year in the United States, and an estimated $18 billion is spent on over-the-counter medications. Both prescription and over-the-counter medications are intended to be consumed by a patient according to specific instructions for dosage and frequency. Non-compliance with these instructions has been identified as a major obstacle to the effective delivery of health care. Compliance typically means consuming the correct dosage at the correct frequency as specified in the prescription or on the over-the-counter medication packaging. According to the World Health Organization, only about half of patients with chronic diseases living in developed countries comply with their medication instructions. The reasons for non-compliance are varied, ranging from simple forgetfulness, to confusion, to ambivalence. However, the effects of non-compliance are staggering, resulting in an estimated $290 billion dollars per year in avoidable medical expenses. Additionally, studies have shown that non-compliance results in about 125,000 deaths annually in the United States, and leads to 10-25 percent of hospital and nursing home admissions.